Keystone was founded as a National Fenestration Rating Council (NFRC) licensed Inspection Agency in 1998 by current president, Marcia Falke, after over 25 years experience in fenestration testing & certification. Jon Hill joined Marcia in 2001 after 17 years of fenestration testing & certification experience, and immediately developed Keystone’s structural and impact certification program. This program was accredited by the American National Standards Institute in March of 2002 (ANSI Accreditation No. 0612). 

In 2004 Keystone developed the Keystone Quality Assurance Program to meet manufacturer needs as a result of the Florida State Product Approval rule 9B-72.   The credibility and scope of the QA program expanded in early 2008 with accreditation by the International Accreditation Service (IAS).

Keystone introduced the Keystone Insulating Glass Certification Program in early 2008 in response to increased demand for this service by the US DOE and NFRC.